[narrator]

There are a lot of people working on converting cargo ships to ammonia fuel. This will at least burn clean producing only nitrogen and water with appropriate engine tech. The ammonia can come from green hydrogen, so it could be 100% clean tech and ammonia doesn't have the problem of needing to be compressed and has good energy density.[1]

[1] https://interestingengineering.com/transportation/worlds-fir...

[mschuster91]

The problem is, shipping is incredibly price sensitive (as evidenced by the industry's SOP of using cheap flag states, exploiting labor and burning bunker fuel aka refinery residue). As long as said refinery residue is cheap, they'll keep the old guzzlers for as long as they can, and only convert a couple "flagships" to ammonia to appease ESG investors.